The present application relates to the transference of information over an air-gap separating a receiver from a transmitter. It finds particular application in the context of computed tomography imaging modalities, where at least one of the transmitter and the receiver is located on a rotating gantry and an airgap separating an input coupler (e.g., for transmitting information) and an output coupler (e.g., for receiving the transmitted information) is small (e.g., 20 mm or less). However, it may also apply to others applications, such as explosive detection machines, radar antennas, etc. where communication signals are wirelessly transferred between a transmitter and a receiver.
Computed tomography (CT) imaging modalities are configured to generate volumetric data corresponding to an object under examination. In this way, three-dimensional images may be generated that allow personnel to identify security threats, determine the orientation/position of a tumor in a body, etc. To generate such data, the computed tomography imaging modality is typically configured to rotate a radiation source and detector array about the object under examination (e.g., causing the object to be viewed from a plurality of angles). For example, the radiation source and/or detector array may be mounted to a rotating gantry configured for rotation relative to a stationary unit configured to support the rotating gantry.
When an object is to be examined, the object is positioned in a bore of the rotating gantry (e.g., between the radiation source and the detector array) and radiation is emitted. Based upon the amount of radiation absorbed and/or attenuated by the object, one or more images of the object may be formed. For example, highly dense aspects of the object typically absorb and/or attenuate more radiation than less dense aspects, and thus an aspect having a higher density, such as a bone or metal, for example, will be apparent in an image when surrounded by less dense aspects, such as muscle or clothing.
Given that the radiation source and detector array are mounted on the rotating gantry, power and control information (e.g., instructing the radiation source and/or other electronic components how to operate) are typically supplied to the rotating gantry from the stationary unit. Moreover, imaging data (e.g., data generated in response to the detection of radiation by the detector array) is typically transferred from the rotating gantry to the stationary unit (e.g., for further processing and/or to be displayed to security/medical personnel).
Conventionally, slip-ring assemblies have been used to transfer power and/or information (e.g., control information and/or imaging data) between the stationary unit and the rotating gantry. Slip-ring assemblies are typically configured to transfer power and/or information between a stationary member and a movable member (e.g., a rotating gantry) and/or between two movable members, through the physical contact of two materials (e.g., via a sliding contact). For example, a slip-ring attached to the stationary member may comprise metal brushes that are configured to physically contact electrically conductive surfaces (e.g., metal brushes) comprised on a slip-ring attached to the movable member, allowing power and/or information to be transferred between the stationary member and the movable member.
While the use of slip-ring assemblies has proven effective for transferring power and/or information between a stationary unit and a movable unit (e.g., such as a rotating gantry) and/or between two movable units, conventional slip-ring assemblies may generate dust or particles (e.g., as metal brushes wear down), may be unreliable (e.g., again as contact surfaces, such as metal brushes, wear and thus may not contact as well), and/or may be noisy (e.g., as surfaces rub against one another), which may cause interference with some procedures (e.g., CT imaging). Other drawbacks of slip-ring assemblies may include cost and complexity of manufacture due to special materials and/or mechanical precision that may be required.